What We've Left Behind
by starspangledlibra
Summary: Nagisa never really explained why he transferred back to Iwatobi, and Mako and Haru never really asked. But Rei did.
1. Chapter 1- Fear

Nagisa never really explained why he transferred back to Iwatobi, and Mako and Haru never really asked. Sure, they had been surprised to see their old childhood friend at Iwatobi High on the first day, but the young blond had simply said that he wanted to go to school with his best friends, and that it was worth taking the train to school every day to be able to see them and swim with them again. And that had been it. The two upperclassmen had never asked Nagisa about his old middle school- not about how his classes had gone, what his teachers were like, or if he'd made any friends that he had to leave behind. They had simply just accepted that Nagisa had returned and didn't question it. They took for granted the presence of the young energetic blond, who had come back into their lives like a whirlwind, dragging them out of the ruts they had been in and taking them along for the ride.

Rei, on the other hand, did ask questions. Granted, he was inquisitive by nature; he would always ask about things that he didn't know or understand. Plus, he was the newest member of the swim club, so naturally he was curious about all of his new friends and teammates. But he was most curious about Nagisa. The boy was a mystery to him in so many ways, largely because he was so different from anyone he'd ever met.

For one thing, Nagisa was impulsive. This was both a good and a bad thing because while he encouraged Rei to try new things, he also tended to get Rei into some sort of trouble at least once a month. Last month, it was trying to swim with the penguins at the aquarium. He didn't even want to think about what it would be this month…

Nagisa was loud. It had taken Rei a long time to get used to having a friend who made so much noise all the time. And this was not an exaggeration; a day spent with Nagisa was literally a day filled with constant noise. If he wasn't talking Rei's ear off, he was humming or singing, or loudly chewing his food. Even when he slept, the boy still made noise, either quiet snoring or incoherent mumbling. And after mulling over his thoughts and feelings on the matter, Rei decided that this wasn't necessarily a bad thing; it was just different from what he was used to. Before Nagisa, his life was filled with quiet- the kind of quiet that comes from having too many books and not enough friends. But now, every morning, his day started with a "HI REI-CHAN!" and a tackle hug, which was highly inappropriate for public transportation. There were always people on the train who would stare, but the regular riders were starting to get used to it. Some had even learned to move out of Nagisa's way as he bounded onto the train and made a beeline for Rei.

That was another thing- Nagisa was extremely affectionate. Most people he knew would only give a verbal greeting to others. They would smile and wave to their friends, but that would be all. But Nagisa would run up to his friends, arms wide open, and hug them like he hadn't seen them in years, even if he had seen them the day before. He would also sit in laps, ruffle hair, tap shoulders, even demand piggyback rides from Mako on occasion. In fact, he was so touchy feely that it had taken Rei an agonizing three months to realize that Nagisa liked him as more than just a friend. But then he had realized that he was the only one who Nagisa would hold hands with, or cuddle in bed with during sleepovers, and then Rei felt stupid for not figuring things out sooner… Now, he was the only person who Nagisa would kiss on the lips, and, well, other places too, of course. Not everywhere though. Not yet.

Yes, Nagisa was a lot of things that most people were not, at least in Rei's opinion. Nagisa was playful, Nagisa was overly cheerful, Nagisa was honest… Nagisa was beautiful… But perhaps the most interesting, as well as the most puzzling, trait that the blond possessed was his bravery. He had no idea where this bravery came from; Nagisa was one of the smallest boys at Iwatobi High. He wasn't weak of course; he did have muscle, but at five foot five and a hundred and twenty pounds, he certainly wasn't the strongest boy in school. Still, nothing seemed to scare the cheerful blond boy- not snakes or spiders, not heights, not the dark, certainly not horror movies…

Not even telling someone that he liked them, maybe even loved them. It had been Nagisa who finally confessed to Rei; much to Rei's chagrin because he had really wanted to be the one to confess first. He'd had it all planned out how he would do it too. But, as Nagisa had said, Rei had taken too long, and he knew that it was because he was nervous and worrying about all the ways that his plans could go wrong. And so, Nagisa had said, in one night, all of the things that Rei had been struggling to put into words for weeks. However, no matter how frustrating it was that he hadn't been the one to confess first, Rei had to admire Nagisa's courage. It took guts to confess first, especially to a boy who had never been the most romantic of people, and yet the words seemed to have come so easily to the smaller boy. But that was just part of what made Nagisa so… Nagisa. He went through life charging headfirst, never slowing down, never holding back, and certainly never fearing what lay ahead.

Which was why Rei was so shocked when he saw a hint of terror in Nagisa's eyes one Friday night. It was only for a second, and it was purely by chance that Rei saw it at all, because the reaction stemmed from such a tiny insignificant detail, or so he thought. He was over at Nagisa's house, in his room, waiting for dinner to be ready. And while they waited, he was telling his new boyfriend about what had happened during that day's joint swim practice at Samezuka. The blond had had to miss practice due to an afterschool dentist appointment, and he wanted to know everything.

"I'm telling you, Nagisa-kun, practice really was not that exciting today."

"Aww, come on," Nagisa said, pouting. "You're really gonna tell me that nothing happened?"

"Well, Haruka and Rin-senpai had a race during time trials."

"Ooh, really? Who won?!"

"Haruka-senpai, but only by a fraction of a second. He says he owes his victory to his new and improved swimsuit, but…" he sighed and shook his head. "It looks exactly the same as all of his other swimsuits."

"But remember, Rei-chan… they all fit differently," he said in a monotone voice, a fake scowl on his face. Then he giggled. "That's what Haru-chan would say!"

"Yeah, you're right; he would say that," Rei agreed with a chuckle. "In fact, I think he actually did say that, after Rin-senpai pointed out that he had a dozen more of the exact same swimsuit at home." This earned another giggle from Nagisa.

"Oh Haru-chan… So what else did I miss?" Anything?"

"Hmm… Not much that I can think of right now… There were two new members who joined the Samezuka swim team today though. They introduced themselves before practice- they're first years just like us. I believe they said they transferred from Yakami."

"Yakami?"

"Yes… Hey, isn't that where you went to middle school?"

"Yeah," Nagisa said slowly, dropping his gaze down onto the bed. "Why?"

"Oh- it's just, I thought… Maybe you might know them. Their names are Akito and Takashi. Both very tall boys, one with orange hair, one with brown… I think the brunette is Akito, and Takashi is the one with… Nagisa?" Rei stopped mid-sentence after taking a look at his boyfriend's face. It seemed paler than it was a minute ago, and he was still avoiding eye contact, which was rare for him. "Nagisa?" he repeated. "Are you all right?" Nagisa jerked his head up to look at Rei, and that's when he saw it: that expression of pure panic- those wide eyes and shrinking pupils. He had seen that look so many times before on Makoto's face, but never on Nagisa's. It left an uneasy feeling in the pit of his stomach.

"Nagisa-kun, is something wrong?" At the taller boy's last question, Nagisa seemed to snap out of his trance. His focus came back from whatever far away place in his mind that it had been, and returned to Rei.

"No- nothing's wrong! Sorry about that Rei; I just kind of… spaced out. I guess I'm just a little tired; classes have been really tough this week- so has practice- and I didn't get much sleep last night… I was up late playing video games," he added with a nervous laugh, as Re shot him a disapproving look.

"Nagisa-kun; you shouldn't make a habit of that; you know you need your sleep. Especially on school nights." He took another look at Nagisa's face. The color was slowly returning to his cheeks, but he still looked paler than he should have. Rei sighed. "Maybe I should just go home after dinner."

"What?"

"You should go to bed early tonight; catch up on your sleep."

"Aww, but Rei-chan, that's no fun! I'm not _that_ tired, and we don't even have school tomorrow, so I can sleep in as long as I want! Besides… I'll sleep better if you're here next to me." He rested his hands on top of Rei's and then leaned in to give him a gentle kiss on the lips. It wasn't a very long kiss, but Rei's whole face felt hot by the time they pulled apart. This kind of affection from Nagisa was still something he had to get used to. Not that he minded getting used to it; he actually quite enjoyed the feeling that it gave him, despite its tendency to impede his ability to think rationally.

Rei was still humming happily to himself and rubbing his lips together when Nagisa leaned in and whispered, "Stay. I'm fine; I promise." And Rei's head was so fuzzy, his heart still so filled with butterflies, that he just nodded dumbly and allowed himself to be kissed again. It was a good few moments later, when his head cleared, and his heartbeat returned to normal, that he remembered his earlier question.

"So, Nagisa-kun; do either of those names sound familiar?" he asked. "The new transfer students at Samezuka?" Nagisa's expression faltered once again, but this time he bounced back much quicker, and that cheerful smile immediately returned to his face. He shook his head.

"Nope; I don't think so! They must have been in a different class! But wow, someone who also went to my old middle school coming to Samezuka right after we start up the joint practices… kind of a funny coincidence, don't you think?" He chuckled as he scooted off the bed, hopping down onto the floor. "Well, I think dinner's almost ready; I'm gonna go see if Mom wants any help setting the table. I'll be right back, ok?"

"Ok…" Rei frowned as he watched his boyfriend turn to leave. Nagisa's performance just now may have fooled most people, but Rei couldn't help but feel he'd just been lied to. Because those wide eyes, shrinking pupils, looking down, face suddenly drained of color... It was easy to diagnose what those were symptoms of.

_Fear. It doesn't suit him_, he decided. He hoped he'd never have to see the smaller boy go through it again, but he bad had a feeling that he probably would.

* * *

_**A/N: **_I'm back! With more angst; I'm so not sorry. Anyway, this fic stems from a personal headcanon of mine about Nagisa's past. I loved watching Free!, but since they didn't give us much of a backstory for Nagisa, I'm doing it myself- or at least trying to fill in a few of the gaps. Anyway, welcome! Hope you all enjoy the read. :3


	2. Chapter 2- Lies

Rei couldn't believe that Nagisa would do something like this. No, actually, he could, and it shocked and appalled him that this type of behavior was becoming the norm. "Nagisa-kun!" Back against the wall, he pushed Nagisa away so that he could have a little breathing room. But the smaller boy just came right back, pressing even closer against Rei's body than before, which he didn't think was possible, but apparently it was.

"Come on, Rei-chan!" A sly smile formed on his face, and he stood up on his tiptoes to whisper in Rei's ear. "I thought you liked my surprises." The suggestive sentence was finished off with a light blowing in his right ear before Nagisa returned to being flat on his feet. "And I thought," he continued, as he ran his fingers up and down Rei's chest, "that I could show you a new surprise today."

At this point Rei's whole face felt like it was on fire. He instinctively went to push up his glasses before realizing that he had already removed them for swim practice, and now he just looked silly. Which made him feel even more embarrassed. "N-not here!" he managed to sputter out, pushing Nagisa away once again, this time a little further back. "Not in the middle of a changing room!"

"But it's not just any changing room- it's Samezuka's changing room! There's a lot more space in here than in our changing room."

"And a lot more people who could just walk in here at any moment and catch us!" As if on cue, the sounds of footsteps and loud chatter made their way into the locker room. "See?"

"But that's what makes it so exciting, don't you think?"

"NO!"

"Aww, Rei-chan, you're no fun," he grumbled, but he moved to pick up his towel and goggles from the floor just as a small cluster of boys walked in. Among those boys were Haru and Mako, who each greeted them with a small, friendly smile.

"Hey guys; you're here early!" said Mako, his eyes settling on Rei. "How'd you manage that?" But before Rei could think of a plausible lie, Nagisa answered for him.

"Oh it was my idea, actually. We came here early to make out!"

"Nagisa-kun!"

"Relax, Rei-chan; these are our friends; they're not going to judge us!"

Mako was speechless; he looked almost as embarrassed as Rei felt. Haru just rolled his eyes. "For kissing, no; for kissing in the middle of a locker room, maybe…"

"Oh really? This coming from they guy who tried to swim in a fish tank?"

"And what exactly is wrong with-"

"We were not making out!" Rei interrupted, perhaps a little too loudly. A couple of the Samezuka boys glanced over in their direction, but if they had heard what he said, they didn't care, and quickly returned to their own conversations. Thankfully. He let out a small sigh of relief and repeated himself, this time much quieter. "We weren't making out. Believe me"

"Yeah, cause you chickened out at the last minute!" Nagisa shot back.

"You're making it sound as if I initially agreed to this!"

"Well you did!"

"I did not!"

"Did too! I asked you if you wanted to go to practice early so we could work on our exchanges, and you said yes!" Mako slapped his forehead and left to go change. Haru shook his head and walked out to the pool area; he was only able to take so much of his first year friends' ridiculous shenanigans at a time. Nagisa didn't seem to notice the freestyle or the backstroke swimmer's absence, however, as his attention was focused solely on Rei. "What did you think I was talking about?"

"I don't know, maybe that you actually wanted to work on our exchanges? For the relay?!" He sighed. "And for a little while, I was so proud, since you've never cared if you were on time for anything, much less early… I thought I was finally starting to rub off on you."

"Nah, you haven't rubbed off on me yet, Rei-chan… But you could if you wanted to… Right now… You know, rub-"

"NAGISA-KUN!"

Nagisa then proceeded to break down into a fit of giggles, and Rei wanted to be irritated; he really did, but the blond's high-pitched bubbly laugh was just too cute, and it wasn't long before his scowl turned into a soft smile. That smile didn't last long though, because the laughter that he found so adorable abruptly stopped merely seconds later. A sharp intake of breath, followed by silence, took its place. Rei frowned. "Nagisa?" The other boy seemed to be in shock, but he quickly snapped out of it when he heard his name.

"Yup; I'm here, sorry! Thought I saw something for a minute!"

"Saw what?"

"Ahh, nothing; let's just go practice, ok?" He pulled on Rei's arm, fiercely tugging him forward. "Come on, Rei-chan; let's go!" They had only taken a few steps towards the door when they heard Nagisa's last name being called out.

"Hazuki? Hazuki!"

Rei's eyes narrowed as he recognized who the voice belonged to. Then he frowned. Until that moment, he had all but forgotten the incident on Friday night, but now as he looked from Nagisa to the two taller first years, it was beginning to come back to him. That sense of fear, anxiety from before; it was back, and it was practically radiating off of the blond as he grimaced and slowly turned around. "Yes?"

"I knew it; I knew I recognized you!" said Akito. "Man, you haven't changed a bit, have you Hazuki?"

"Nope," Takashi agreed. "Still the same small fry of the swim club, ehh Hazuki? Ha! I'm just kidding!" he added, after he noticed the look that Rei was giving him. "But anyway, how've you been? It's been so long since we've seen you. Gotta say, I didn't think we were ever gonna see you again, you know… after you left in eighth grade."

"Yeah, me neither."

"So where'd you end up at anyway? Before Iwatobi I mean."

"Oh, just- somewhere closer to home," Nagisa said airily. "The commute was getting to be too expensive since my dad was between jobs at the time." His usual friendly smile was plastered onto his face, but Rei could tell that the blond did not want to say anything more on the subject. Still, he was curious- why was this the first he was hearing about Nagisa changing middle schools? Why did Nagisa seem so reluctant to share where the second school was? He didn't know for sure, but he had a feeling that it had something to do with the two smiling boys in front of him. Akito seemed harmless enough, but Takashi? It seemed as if there was something hidden beneath his smile as well, and whatever it was, Rei didn't like it. Instinctively, he took a step closer to Nagisa and gripped his arm tightly.

"Ahh, that's too bad," said Takashi. "Me and the other guys really missed hanging out with you after practice. I'll tell you, you're not an easy guy to replace."

Another grimace from the blond. "I'm sure you managed."

"Yeah, but… hey, how about we catch up sometime, just the three of us? Or maybe we can get the whole gang together- I'm sure they'd all love to see you again!"

Silence. A shaky intake of breath, and then, "T-the whole gang?" The two boys nodded in confirmation.

"All of them."

"Oh, that sounds uhh…"

"We're late for swim practice," Rei said coolly, effectively breaking the tension in the room. "Come on, Nagisa-kun, let's go. You can catch up with them later if you want, but right now, you need to focus on your breaststroke." He turned to Takashi and Akito and bowed his head slightly. "It was nice to meet of Nagisa's old um- friends. I'm sure we'll see you later… Welcome to Samezuka," he added tentatively before dragging his boyfriend out to the pool area. And as they walked in silence, his head was buzzing with questions. He knew they didn't have much time though- practice really was about to start, and he knew that Takashi and Akito would be quick to follow them out, so instead of asking every question on his mind, he settled for one. Actually, it wasn't really a question. More of an accusation.

"I thought you said you didn't know them."

Nagisa must have seen this question coming, however, because without missing a beat, he replied with, "I did? Oh yeah, I did! They were in the same swim club as me; I forgot their names though- it's kind of embarrassing! But once I saw their faces I… I remembered who they were."

"I could tell."

At this, Nagisa stared at Rei, his dark pink eyes locked onto him, as if to try and gauge what he meant by that statement. But after a minute of this, he shook his head and laughed. "I know I know; I'm so forgetful," he chided himself lightly. But don't worry Rei-chan, I'll make it up to them!"

Rei didn't even have time to ask what that entailed because the next thing he knew; Nagisa was shoving a towel in his face and cannonballing into the pool. He shot an exasperated look at his boyfriend when he surfaced, who only offered him a cheeky grin in return. Rei sighed. He had been hoping for a mature, honest conversation about why he'd been lied to on Friday. Because it was clear that from what had just happened, he not only knew those boys, but he had a history with them. What kind of history- he still needed to figure that out, but he could only assume that whatever relationship Nagisa had with Takashi in the past, it had ended badly. So when Takashi and Akito finally came out of the locker room, Rei rushed to join Nagisa in the pool. This friendly pretense that they had going was only temporary, after all. It could only be kept up for so long…

* * *

_**A/N:**_Oh wow it has been so long! To anyone reading, I'm really sorry that this chapter took so long- I had a bit of writer's block, but mostly it was midterms kicking my butt that kept me from writing. Anyway, I'm back though and this story will begin to pick up soon, I promise, so I hope you guys stick around! And, as always, thanks for reading :)


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